The Effect of pH Variation in Irrigation Water on the Growth Performance of Brassica rapa

• Sam M Moffit

  Juniata College

  Author

• Kara M Scotti

  Juniata College

  Author

• Ella C Whitman

  Juniata College

  Author

This study aimed to investigate how varying pH levels of water affect the growth of Brassica rapa plants. Brassica rapa plants were planted in equal size containers and kept in a greenhouse where they were irrigated with equal amounts of different pH levels (3, 5, 7, 9, and 11) of water every 2-3 days. The experiment aimed to assess how pH levels influence plant growth and development and is relevant to field research of acid rainfall and mine drainage.The results revealed notable differences in growth patterns among the Brassica rapa. Beginning with germination, we noted that out of the 15 seeds planted for each pH, there were many that did not successfully germinate. Most notably were plants irrigated with alkaline water, with the pH 11 water having 10 of the 15 plants never sprout, and pH 9 which had 6 plants fail to germinate. Surprisingly, the plants watered with the very acidic water (pH 3), displayed the least number of failed plants (3). Based off our results, the pH 3 water and pH 7 water displayed the most vigorous growth, while those exposed to pH 5 and 9 exhibited slower development. As seen with failed germinations, the plants irrigated with pH 11 water exhibited signs of limited growth. Further analysis indicated that pH levels may have influenced plant’s ability to absorb nutrients from the soil, impacting plant growth. The findings suggest a complex interplay between pH levels, nutrient uptake, and plant physiology in Brassica rapa plants. We noted in this study that the plants watered with pH 11 were consistently found with dry soil, despite all plants being irrigated with the same amount of water. The dry soil surrounding the plants suggests that they were not effectively retaining moisture. This could be due to increased evaporation rates due to higher pH, or hindered nutrient uptake which may have caused the plants to uptake more water.

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